A wireless communications network may have various known problems that limit the effectiveness of that communications network. These known problems are particularly concerning in an ad-hoc wireless network wherein a central fixed server may not be present. In a typical wireless communications network, it is desirable for push-to-talk communications to occur within arbitrary groups. However, in a typical wireless communications system, the push-to-talk communications occur on a specific radio channels. In the IP environment, multicasting does not react fast enough to changes in the network such as can be seen by roaming clients. The limited capability of underlying router infrastructure to adjust to changes is difficult to use correctly and involves long delays. Moreover, multicasting has limitations in the number of groups that can be targeted.
In a typical wireless communications system, two groups that are defined separately might be given the same identifier, i.e. the same name. Thus, later, when those two groups are reachable from each other, perhaps on the same subnet in the communications network, the identifiers can collide resulting in communication confusion. It is desirable to provide each group with a unique identification to prevent collisions. Furthermore, when a user wishes to listen to several groups, there may be some confusion that one group will be heavily used and of less importance than speech on a less used group and this makes it difficult for the user to listen to both groups effectively.
The typical wireless communications network also has security concerns. In particular, denial of service “attacks” can occur either accidentally or maliciously. For example, a device that malfunctions or is otherwise left in a transmitting state can deny service to listeners, which can occur even in a secure network. If the security of a network is breached, perhaps by someone taking control of a device belonging to someone legitimately within that network, then such denial of service can occur maliciously. Refusing to listen to a specific group denies all transmitters to the group the right to be heard, but there can be no alternative to a denial of service attack. It is desirable to provide a mechanism to obviate a denial of service attack.
In a typical wireless communications network, it is generally not possible for a listener to interrupt a push-to-talk speaker to request him to repeat what he has said. However, it is desirable to provide repetition as it is sometimes necessary for the listener to understand the speaker. A listener may alternately need to quickly change a push-to-talk session into a two-way conversation of some kind which is not possible with a typical wireless communications system. A standard phone call requires call announcement, usually a ring, which can be disruptive, unwanted, and time consuming relative to push-to-talk. With a typical wireless communications network, connectivity between sender and receiver may be interrupted arbitrarily due to various events, such as if on a wireless LAN a user may walk out of range, or on an Ad-hoc 802.11 network, two users might wander out of each other's range.
For push-to-talk, it is desirable for organizations with like structures to be configured similarly for push-to-talk communications. It is further desirable for configurations to be combined for some or all of the users of those configurations. Furthermore, encryption of the communications between groups may be desirable or required. In addition, the presence of members, whether they have spoken or not, on a subnet is not automatic. A user may have transmitted some time back, but no longer be present on the subnet. This may lead to an attempt to contact him unnecessarily.
Thus, it is desirable to provide an ad hoc wireless communications network that overcomes these problems with typical wireless communications systems and it is to this end that the present invention is directed.